It is known to enter the end of an instrument guide (e.g. trocar tube) into a surgical site, and telescopically guide through the instrument guide various elongate surgical instruments into the surgical site. In one example, a sharply pointed piercing instrument of elongate dimension (e.g. a trocar) is inserted telescopically through an instrument guide. The point of the trocar is then used to make an incision in the patient at the surgical site and the adjacent end of the instrument guide is inserted into the incision. The trocar is then withdrawn from the instrument guide and set aside. Thereafter, a desired sequence of surgical instruments can be inserted telescopically through the instrument guide into the surgical site. Techniques of this known type are used in a variety of surgical procedures, for example, on a larger scale, laparoscopy or, on a smaller scale, arthroscopic joint surgery, such as arthroscopic knee surgery.
Such elongate surgical instruments insertable through such an instrument guide include instruments allowing the surgeon vision into the surgical site, which may be provided with a leading tip of transparent material such as glass or clear plastic and which may include lighting, direct vision and/or camera means.
Such elongate surgical instruments also include a variety of cutting or other tissue modifying instruments. The latter may have surface irregularities near the distal working tip, e.g. grooves, etc.
It is known to inject gas under pressure into the surgical site, through the instrument guide, or otherwise, to enlarge the surgical cavity, e.g. to allow the surgeon better vision of the tissue to be surgically treated or modified or to allow the surgeon more room in which to manipulate instruments to carry out the surgical procedure. To avoid loss of pressure gas from the surgical site through the instrument guide, the latter typically has a resilient annular seal remote from the surgical site and which sealingly surrounds the surgical instrument.
The prior art has made several attempts to block loss of pressure gas from the surgical site with no surgical instrument in the instrument guide.
For example, it has been known to provide a so-called trumpet valve on the instrument guide between the surgical site and the annular resilient seal. More particularly, the trumpet valve comprises a cylindrical valve core movable in a cylindrical passage communicating at right angles with the longitudinal passage of the instrument guide. A spring urges the cylindrical valve core axially in one direction to close the longitudinal passage in the instrument guide. An external push button can be pushed by the surgeon to displace the cylindrical valve core so that the longitudinal passage in the instrument guide registers coaxially with a diametral hole in the valve core of identical diameter so that an elongate surgical instrument can be telescopically inserted through and withdrawn from the instrument guide. However, while generally satisfactory, Applicant has found that such a trumpet valve construction has disadvantages. For example, it requires an extra hand to operate the trumpet valve push button, hold the instrument guide in place, and remove or insert a surgical instrument. Further, such a trumpet valve construction requires excessively tight tolerances in manufacturing to perform properly in the field, is expensive to manufacture, and can involve difficulties in disassembly for sterilization purposes and reassembly thereafter.
Another prior art apparatus has instead utilized a trap door valve, in the form of a plate-like valve member which is hinged and spring biassed to swing against an annular valve seat enclosed in a radially enlarged chamber intermediate the ends of the instrument guide. One such prior trap door valve utilizes a trap door with a convex ball-shaped face opposing the seat. A coiled torsion spring is wound around a fixed pin skewed with respect to the instrument passage axis and has one end extending lever-like and fixedly supporting the ball-faced member, to act both as a pivot hinge and a resilient biassing element. The annular valve seat is coaxial with the instrument passage and the center of the ball-like movable valve member lies on the instrument passage axis in its closed position. Applicant has noted disadvantages with prior apparatus of this kind. For example, the initial incision in the surgical site is to be made by a sharp, pointed obturator and it is critical that the point of the obturator be maintained sharp up to the time it reaches the skin of the patient and makes the incision thereof. However, to open trap door valves of the above-mentioned kind, the sharp point of the obturator must push against the movable trap door valve member and swing it out of the way so that the obturator can proceed therepast and into the surgical site. If the opposed trap door face is of relatively soft material, the sharp point of the obturator will tend either to dig into and fail to open the trap door member or to damage the surface thereof against future use. On the other hand, if the opposed trap door face is of relatively hard material, the latter may blunt or dull the point of the obturator as such point skids along the trap door face in the process of pushing it out of the way. Moreover, successive surgical instruments passing through the instrument guide to the surgical site or being pulled out of the surgical site must also push open the trap door member. Instruments having a transparent or otherwise delicate distal tip could be damaged by scuffing along the surface of the trap door valve member in the process of opening it. Moreover, irregularly shaped instrument distal portions, for example some cutting or other tissue modifying heads, may also tend to snag on the opposed trap door face as they attempt to push it aside to reach the surgical site, or may snag on the free edge of the trap door valve member while attempting to withdraw outward past it.
Another prior art apparatus is known in which an instrument guide is sealed by means of a rubber, washer-like member with a hole cut not quite all the way therethrough. The valve member is mounted on top of the instrument guide in the same manner as a washer and when an instrument is inserted into the instrument guide it breaks through the thinnest part of the washer material and pushes aside adjacent parts of the washer material in the manner of a flap or flaps opening, such that the instrument can be inserted through the instrument guide. This type of valve is used for simple instrument guide designs and is useful for inexpensive disposable devices. However, the valve does not provide an air-tight seal when the instrument is withdrawn from the instrument guide.
Accordingly, it is an object of the present invention to overcome certain difficulties in prior art apparatus of this general kind.
Other objects and purposes of the present invention will be apparent to persons acquainted with apparatus of this general type upon reading the following description and inspecting the accompanying drawings.
One aspect of the invention includes apparatus for guiding insertion of surgical instruments into a surgical site while blocking escape of fluids, such as gas under pressure, therethrough from the surgical site. Such apparatus comprises elongate instrument and valve passages intersecting at an acute angle with a valve seat adjacent their intersection and a valve member movable along the valve passage toward the valve seat for blocking fluid escape from the surgical site when no instrument is in the instrument passage and alternatively for being moved away from the valve seat by insertion of an instrument through the instrument passage, for allowing entry of an instrument to the surgical site.